Texas Instruments LP2985IM5X-3.8/NOPB

Overview

LP2985IM5X-3.8/NOPB from Texas Instruments is a micropower, ultra-low-dropout linear regulator delivering 150 mA output current with 3.8 V fixed output voltage, 300 mV typical dropout at full load, 1% output accuracy (A-grade), and 30 µV_RMS output noise (300 Hz–50 kHz) when using a 10-nF bypass capacitor. It serves as a low-noise power supply for battery-powered portable electronics requiring stable, precision voltage rails.

For engineers reviewing the LP2985IM5X-3.8/NOPB datasheet, LP2985IM5X-3.8/NOPB pinout, LP2985IM5X-3.8/NOPB application, or LP2985IM5X-3.8/NOPB equivalent, key selection criteria include its SOT-23-5 package footprint, ON/OFF logic control interface, compatibility with low-ESR ceramic capacitors (≥2.2 µF), shutdown quiescent current < 1 µA, and thermal/overcurrent protection - all critical for space-constrained, energy-sensitive designs.

Technical Context

The LP2985IM5X-3.8/NOPB employs a vertically integrated PNP (VIP) pass transistor architecture enabling ultra-low dropout (280–575 mV at 150 mA over temperature) and low ground current (75 µA at 1 mA, 850 µA at 150 mA). Its internal reference and feedback loop deliver 1% initial output accuracy and ±3.5% total error over –40°C to 125°C junction temperature.

It integrates an active ON/OFF control input (logic-high enable, <0.15 V disable threshold), BYPASS pin for noise filtering via external 10-nF capacitor, and foldback current limiting with thermal shutdown. Stability is ensured with output capacitors having ESR as low as 5 mΩ - optimized specifically for ceramic types.

Key Specifications

Pinout & Package

LP2985IM5X-3.8/NOPB is housed in a 5-pin SOT-23 package (2.90 mm × 1.60 mm body size), surface-mountable with standard reflow profiles and rated for –40°C to 125°C junction temperature.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Compared with LP2985IM5X-3.8/NOPB, TCS2115-3.8 trades noise performance and accuracy for lower unit cost, while MCP1703T-3802E/MB offers greater current headroom but sacrifices integrated enable functionality and ultra-low dropout - making LP2985IM5X-3.8/NOPB optimal for noise-critical, battery-gated, space-constrained systems.

Availability

LP2985IM5X-3.8/NOPB is available at Aetrix Electronics and suitable for cellular handsets, wearable sensor nodes, industrial data loggers, and medical point-of-care monitors requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LP2985IM5X-3.8/NOPB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company designing analog ICs, embedded processors, and system solutions for industrial, automotive, and personal electronics markets.

The LP2985-N product line delivers micropower, ultra-low-dropout, low-noise LDO regulators optimized for battery-powered portable equipment where small size, high accuracy, and minimal quiescent current are essential.

FAQ

What is the minimum input voltage required for LP2985IM5X-3.8/NOPB to regulate 3.8 V output?

The LP2985IM5X-3.8/NOPB requires a minimum input voltage of 3.1 V under recommended operating conditions. This accounts for worst-case dropout (575 mV at 150 mA and full temperature range), ensuring the device maintains regulation across all loads and temperatures. At light loads (1 mA), dropout drops to 7 mV, allowing operation with VIN as low as 3.807 V.

Does LP2985IM5X-3.8/NOPB require an external bypass capacitor to achieve its specified 30 µV_RMS noise performance?

Yes, LP2985IM5X-3.8/NOPB achieves 30 µV_RMS output noise (300 Hz–50 kHz) only when a 10-nF ceramic capacitor is connected between the BYPASS pin and GND. Without this capacitor, output noise rises significantly. The BYPASS pin directly filters the internal reference, making this capacitor essential for low-noise applications like precision ADCs or RF receivers.

Can LP2985IM5X-3.8/NOPB be used with a 2.2 µF output capacitor, and what ESR range is acceptable?

Yes, LP2985IM5X-3.8/NOPB is explicitly designed for stability with a minimum 2.2 µF ceramic output capacitor and ESR as low as 5 mΩ. Unlike older LDOs, it does not require high-ESR tantalum capacitors. The device remains stable across the full 150 mA load range with ESR values within this low range - enabling smaller, more reliable, and lower-cost ceramic solutions.

What happens to LP2985IM5X-3.8/NOPB when the ON/OFF pin voltage is between 0.15 V and 1.6 V?

When the ON/OFF pin voltage of LP2985IM5X-3.8/NOPB falls within the indeterminate range of 0.15 V to 1.6 V, the device may enter an undefined state - potentially oscillating between enabled and disabled modes or exhibiting erratic output behavior. TI specifies clear thresholds: ≤0.15 V guarantees shutdown (<2 µA I_Q), and ≥1.6 V guarantees reliable startup. External pull-up/pull-down resistors are recommended to avoid this region.

Is LP2985IM5X-3.8/NOPB RoHS-compliant and lead-free?

Yes, LP2985IM5X-3.8/NOPB is RoHS-compliant and lead-free. The "/NOPB" suffix in the part number explicitly denotes "No Lead (Pb)-Free", confirming compliance with EU RoHS Directive 2011/65/EU and JEDEC J-STD-609 standards. The SOT-23 package uses matte tin (Sn) lead finish and meets TI's green packaging requirements.